This invention relates to automatic calling line identification in telecommunications systems.
Calling line identification is a very popular service. It allows the user of the service to identify the caller and to either be prepared to talk to that caller, or to ignore the call.
In recent years, calling line identification has been further enhanced by providing the name of the owner of the telephone line or mobile station that is making a call. Thus, the called party need not be able to recognize the caller""s telephone number, but can simply see the caller""s name.
A problem with presently available calling line identification is that if the call has been transferred, the identification that the called party receives is the identification of the line and name of the party from which the call was transferred.
Applicants have further analyzed this problem and have recognized that the ideal solution is to provide the original caller""s identification to a called party, i.e., to any station that is alerted for the call.
Applicants have solved the above problem and have made a contribution over the teachings of the prior art in accordance with their invention, wherein if a call is transferred from another line, the called party sees a calling line identification display or hears a calling line identification announcement that corresponds to the original caller""s identification, not to the identification of the line from which a call was transferred. For calls that are transferred, the original calling line identification, possibly enhanced by the name associated with the caller""s telephone number, is retained by the transferring switch and is inserted into the calling line identification field of the signaling message between the transferring switch and the terminating switch. The terminating switch will then send or announce to the called party the telephone number and/or name of the caller as received in the signaling message, not the name and/or telephone number of the transferring party.
In accordance with one aspect of Applicants"" invention, for customers having a transfer feature or three-way calling feature, when a call to such customer is made, the switching system serving that customer retains the caller""s identification. Subsequently, if the called party transfers the call to a third party, the signaling message (for inter-office calls) or the calling line identification message, uses the retained information, not information associated with the party which originally answered the call. The basic principle, that on all transferred calls, the calling lines identification information is retained in the calling line identification field of the signaling message, makes implementation of this feature a straightforward process.